package android.app.gfestival.adapter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.util.HashMap;
import java.util.Stack;

import android.app.Activity;
import android.app.gfestival.R;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.widget.ImageView;

        public class ImageLoader {

            //the simplest in-memory cache implementation. This should be replaced with something like SoftReference or BitmapOptions.inPurgeable(since 1.6)
            private HashMap<String, Bitmap> cache = new HashMap<String, Bitmap>();
            //private HashMap<String, Bitmap> cache=new HashMap<String, Bitmap>();

            private File cacheDir;

            public ImageLoader(Context context) {
                //Make the background thead low priority. This way it will not affect the UI performance
                photoLoaderThread.setPriority(Thread.NORM_PRIORITY - 1);

                //Find the dir to save cached images
                if (android.os.Environment.getExternalStorageState().equals(
                        android.os.Environment.MEDIA_MOUNTED)) {
                    cacheDir = new File(android.os.Environment
                            .getExternalStorageDirectory(), "LazyList");
                    System.out
                            .println("cacheDir:" + cacheDir.getAbsolutePath());
                } else
                    cacheDir = context.getCacheDir();
                if (!cacheDir.exists())
                    cacheDir.mkdirs();
            }

            // final int stub_id=R.drawable.stub;
            final int stub_id = R.drawable.icon;

            public void DisplayImage(String url, Activity activity,
                    ImageView imageView) {
                System.out
                        .println("Called from DisplayActivity and url " + url);
                if (cache.containsKey(url))
                    imageView.setImageBitmap(cache.get(url));
                else {
                    queuePhoto(url, activity, imageView);
                    imageView.setImageResource(stub_id);
                }
            }

            public void DisplayImage(String url, Context context,
                    ImageView imageView) {
                if (cache.containsKey(url))
                    imageView.setImageBitmap(cache.get(url));
                else {
                    queuePhoto(url, context, imageView);
                    imageView.setImageResource(stub_id);
                }
            }

            private void queuePhoto(String url, Activity activity,
                    ImageView imageView) {
                //This ImageView may be used for other images before. So there may be some old tasks in the queue. We need to discard them. 
                photosQueue.Clean(imageView);
                PhotoToLoad p = new PhotoToLoad(url, imageView);
                synchronized (photosQueue.photosToLoad) {
                    photosQueue.photosToLoad.push(p);
                    photosQueue.photosToLoad.notifyAll();
                }

                //start thread if it's not started yet
                if (photoLoaderThread.getState() == Thread.State.NEW)
                    photoLoaderThread.start();
            }

            private void queuePhoto(String url, Context context,
                    ImageView imageView) {
                //This ImageView may be used for other images before. So there may be some old tasks in the queue. We need to discard them. 
                photosQueue.Clean(imageView);
                PhotoToLoad p = new PhotoToLoad(url, imageView);
                synchronized (photosQueue.photosToLoad) {
                    photosQueue.photosToLoad.push(p);
                    photosQueue.photosToLoad.notifyAll();
                }

                //start thread if it's not started yet
                if (photoLoaderThread.getState() == Thread.State.NEW)
                    photoLoaderThread.start();
            }

            private Bitmap getBitmap(String url) {
                //I identify images by hashcode. Not a perfect solution, good for the demo.
                String filename = String.valueOf(url.hashCode());
                File f = new File(cacheDir, filename);

                //from SD cache
                Bitmap b = decodeFile(f);
                if (b != null)
                    return b;

                //from web
                try {
                    Bitmap bitmap = null;
                    InputStream is = new URL(url).openStream();
                    OutputStream os = new FileOutputStream(f);
                    Utils.CopyStream(is, os);
                    os.close();
                    bitmap = decodeFile(f);
                    return bitmap;
                } catch (Exception ex) {
                    try {
                        Bitmap bitmap = null;
                        url = "http://a1.twimg.com/profile_images/1148249687/eventur_1_bigger.png";
                        InputStream is = new URL(url).openStream();
                        OutputStream os = new FileOutputStream(f);
                        Utils.CopyStream(is, os);
                        os.close();
                        bitmap = decodeFile(f);
                        return bitmap;
                    } catch (Exception e) {

                    }
                    ex.printStackTrace();
                    return null;
                }
            }

            //decodes image and scales it to reduce memory consumption
            private Bitmap decodeFile(File f) {
                try {
                    //decode image size
                    BitmapFactory.Options o = new BitmapFactory.Options();
                    o.inJustDecodeBounds = true;
                    BitmapFactory.decodeStream(new FileInputStream(f), null, o);

                    //Find the correct scale value. It should be the power of 2.
                    final int REQUIRED_SIZE = 70;
                    int width_tmp = o.outWidth, height_tmp = o.outHeight;
                    int scale = 1;
                    while (true) {
                        if (width_tmp / 2 < REQUIRED_SIZE
                                || height_tmp / 2 < REQUIRED_SIZE)
                            break;
                        width_tmp /= 2;
                        height_tmp /= 2;
                        scale *= 2;
                    }

                    //decode with inSampleSize
                    BitmapFactory.Options o2 = new BitmapFactory.Options();
                    o2.inSampleSize = scale;
                    return BitmapFactory.decodeStream(new FileInputStream(f),
                            null, o2);
                } catch (FileNotFoundException e) {
                }
                return null;
            }

            //Task for the queue
            private class PhotoToLoad {
                public String url;
                public ImageView imageView;

                public PhotoToLoad(String u, ImageView i) {
                    url = u;
                    imageView = i;
                }
            }

            PhotosQueue photosQueue = new PhotosQueue();

            public void stopThread() {
                photoLoaderThread.interrupt();
            }

            //stores list of photos to download
            class PhotosQueue {
                private Stack<PhotoToLoad> photosToLoad = new Stack<PhotoToLoad>();

                //removes all instances of this ImageView
                public void Clean(ImageView image) {
                    for (int j = 0; j < photosToLoad.size();) {
                        if (photosToLoad.get(j).imageView == image)
                            photosToLoad.remove(j);
                        else
                            ++j;
                    }
                }
            }

            class PhotosLoader extends Thread {
                public void run() {
                    try {
                        while (true) {
                            //thread waits until there are any images to load in the queue
                            if (photosQueue.photosToLoad.size() == 0)
                                synchronized (photosQueue.photosToLoad) {
                                    photosQueue.photosToLoad.wait();
                                }
                            if (photosQueue.photosToLoad.size() != 0) {
                                PhotoToLoad photoToLoad;
                                synchronized (photosQueue.photosToLoad) {
                                    photoToLoad = photosQueue.photosToLoad
                                            .pop();
                                }
                                Bitmap bmp = getBitmap(photoToLoad.url);
                                cache.put(photoToLoad.url, bmp);
                                Object tag = photoToLoad.imageView.getTag();
                                if (tag != null
                                        && ((String) tag)
                                                .equals(photoToLoad.url)) {
                                    BitmapDisplayer bd = new BitmapDisplayer(
                                            bmp, photoToLoad.imageView);
                                    Activity a = (Activity) photoToLoad.imageView
                                            .getContext();
                                    a.runOnUiThread(bd);
                                }
                            }
                            if (Thread.interrupted())
                                break;
                        }
                    } catch (InterruptedException e) {
                        //allow thread to exit
                    }
                }
            }

            PhotosLoader photoLoaderThread = new PhotosLoader();

            //Used to display bitmap in the UI thread
            class BitmapDisplayer implements  Runnable {
                Bitmap bitmap;
                ImageView imageView;

                public BitmapDisplayer(Bitmap b, ImageView i) {
                    bitmap = b;
                    imageView = i;
                }

                public void run() {
                    if (bitmap != null)
                        imageView.setImageBitmap(bitmap);
                    else
                        imageView.setImageResource(stub_id);
                }
            }

            public void clearCache() {
                //clear memory cache
                cache.clear();

                //clear SD cache
                File[] files = cacheDir.listFiles();
                for (File f : files)
                    f.delete();
            }

        }